/* OS dependent filename manipulation routines */
#include "filename.h"
#include <string.h>

extern FILE *safe_fopen( const char *fnm, const char *mode ) {
   return ( fDirectory(fnm) ? (FILE *)NULL : fopen( fnm, mode ) );
}

extern char * FAR PthFromFnm( const char *fnm ) {
   char *pth;
   const char *lf;
   int lenpth = 0;

   lf = strrchr( fnm, FNM_SEP_LEV );
#ifdef FNM_SEP_LEV2
   if (!lf) lf = strrchr( fnm, FNM_SEP_LEV2 );
#endif
#ifdef FNM_SEP_DRV
   if (!lf) lf = strrchr( fnm, FNM_SEP_DRV );
#endif
   if (lf) lenpth = lf - fnm + 1;

   pth = osmalloc( lenpth + 1 );
   strncpy( pth, fnm, lenpth );
   pth[lenpth] = '\0';

   return pth;
}

extern char * FAR LfFromFnm( const char *fnm ) {
   char *lf;
   if ((lf = strrchr( fnm, FNM_SEP_LEV )) != NULL
#ifdef FNM_SEP_LEV2
       || (lf = strrchr( fnm, FNM_SEP_LEV2)) != NULL
#endif
#ifdef FNM_SEP_DRV
       || (lf = strrchr( fnm, FNM_SEP_DRV )) != NULL
#endif
       ) {
      return osstrdup(lf + 1);
   }
   return osstrdup(fnm);
}

/* Make fnm from pth and lf, inserting an FNM_SEP_LEV if appropriate */
extern char * FAR UsePth( const char *pth, const char *lf ) {
   char *fnm;
   int len, len_total;
   bool fAddSep = fFalse;

   len = strlen(pth);
   len_total = len + strlen(lf) + 1;

   /* if there's a path and it doesn't end in a separator, insert one */
   if (len != 0 && pth[len-1] != FNM_SEP_LEV) {
#ifdef FNM_SEP_LEV2
      if (pth[len-1] != FNM_SEP_LEV2) {
#endif
#ifdef FNM_SEP_DRV
         if (pth[len-1] != FNM_SEP_DRV) {
#endif
            fAddSep = fTrue;
            len_total++;
#ifdef FNM_SEP_DRV
         }
#endif
#ifdef FNM_SEP_LEV2
      }
#endif
   }

   fnm = osmalloc(len_total);
   strcpy( fnm, pth );
   if (fAddSep) fnm[len++] = FNM_SEP_LEV;
   strcpy( fnm+len, lf );
   return fnm;
}

/* Add ext to fnm, inserting an FNM_SEP_EXT if appropriate */
extern char * FAR AddExt( const char *fnm, const char *ext ) {
   char * fnmNew;
   int len, len_total;
#ifdef FNM_SEP_EXT
   bool fAddSep = fFalse;
#endif

   len = strlen(fnm);
   len_total = len + strlen(ext) + 1;
#ifdef FNM_SEP_EXT
   if (ext[0] != FNM_SEP_EXT) {
      fAddSep = fTrue;
      len_total++;
   }
#endif

   fnmNew = osmalloc(len_total);
   strcpy( fnmNew, fnm );
#ifdef FNM_SEP_EXT
   if (fAddSep) fnmNew[len++] = FNM_SEP_EXT;
#endif
   strcpy( fnmNew+len, ext );
   return fnmNew;
}

/* fopen file, found using pth and fnm
 * pfnmUsed used to return filename used to open file (ignored if NULL)
 * or NULL if file didn't open
 */
extern FILE FAR * fopenWithPthAndExt( const char * pth, const char * fnm, const char * szExt, const char * szMode,
                                      char **pfnmUsed ) {
  char *fnmFull = NULL;
  FILE *fh = NULL;
  bool fAbs;
  /* if no pth treat fnm as absolute */
  fAbs = (pth == NULL || *pth == '\0' || fAbsoluteFnm(fnm));

  /* if appropriate, try it without pth */
  if (fAbs || fAmbiguousFnm(fnm)) {
    fh = safe_fopen(fnm, szMode);
    if (fh) {
      if (pfnmUsed) fnmFull = osstrdup(fnm);
    } else {
      if (szExt && *szExt) { /* szExt!="" => got an extension to try */
        fnmFull = AddExt( fnm, szExt );
        fh = safe_fopen( fnmFull, szMode );
      }
    }
  }

  /* if filename could be relative, and file not opened yet */
  if (!fAbs && fh == NULL) {
    osfree(fnmFull);
    /* try using path given - first of all without the extension */
    fnmFull = UsePth( pth, fnm );
    fh = safe_fopen( fnmFull, szMode );
    if (!fh) {
      if (szExt && *szExt) {
        /* we've been given an extension so try using it */
        char *fnmTmp;
        fnmTmp = fnmFull;
        fnmFull = AddExt( fnmFull, szExt );
        osfree(fnmTmp);
        fh = safe_fopen( fnmFull, szMode );
      }
    }
  }

  /* either it opened or didn't. If not, fh==NULL from safe_fopen() */
  if (fh == NULL || pfnmUsed == NULL)
    osfree(fnmFull); /* free name if it didn't open or name isn't wanted */
  if (pfnmUsed) *pfnmUsed = (fh ? fnmFull : NULL);
  return fh;
}